Studies are being performed with the overall objective of elucidating the mechanisms of water and electrolyte transport in the cornea and determining the role of these mechanisms in the maintenance of corneal transparency. Specifically the work at present is oriented towards: a) the determination of the electrical characteristics of the corneal layers, i.e., the epithelium, the stroma and the endothelium, b) the ion selectivities of the various layers of the cornea, c) determination of the conductances of the limiting membranes of the epithelium and endothelium, and d) determination of the potential differences across the limiting plasma membranes of the corneal epithelial and endothelial cells by mean of microelectrodes and fluorescent dyes.